I installed new after market trunk struts and the lift is still quite heavy. Is this normal or did I buy the wrong struts?

 

The initial lift of the trunk is heavy, but once it is open about 12" the struts take over and open it the rest of the way.
When closing it is pretty much the reverse. You pull down until about 10" from closed and then the weight & soft-close takes over.
Mine has after-market struts and they behave just like the OEM ones did before one of them failed.

 

Thank you for this information. I am new to Lexus and I originally expected the trunk to open fully by itself.
A.R.

 

Even with new struts opening the trunk on the LS430 for the first 6 inches or so is actually way more difficult then it should be. All LS430 trunklids feel super heavy to open.
The struts are primarily designed to not allow the trunk to fall hard from fully open position and to slow the trunk lid down as it descends the last 12 inches or so, stopping it from slamming down hard. The LS430 trunklid operation is a poor design, especially in relation to how well the rest of the car is designed.

 

3 years ago bought "A-Premium Rear Tailgate Lift Supports Shock Struts Compatible with Lexus LS430" for $16.99 on Amazon. Still working great, very satisfied....
Takes some effort to open first several inches then as angle increases effort lessons at about 20-30' deck lid will stay in place at about 70' deck lid will move on its own to fully open.
To close take a little effort to start the close then at maybe 20' (some inches from fully closed) deck lid will close on its own if let go.

 

Agree that the design, compared to the modern electric lift options, for LS430s is poor. After a strut failure the replacements (in my case, Strong Arm) worked like OEM. Difficult to open the first 12” or so but then the lid goes up and stays in place. The closing process I always grab the handle to pull the lid down and guide it to a soft landing with a final light “push” so the closing mechanism finishes the process.

When my wife drove this as her daily (she is now spoiled by a 460) she let the lid drop with a slam; that habit explained all of the tail light alarms due to the sockets being rattled that either the bulb filaments gave out or the connectors coming loose.

Regardless of brand, always replace failed or weak struts as the lid will leave a mark for sure….